Automated transaction machines (e.g. vending machines, gaming machines, ATMs, etc.) typically accept items of currency in exchange for goods and/or services. Items of currency are typically inserted into an automated transaction machine, and are evaluated by an authentication unit to determine if they are genuine or non-genuine. In some forms of currency (e.g. banknotes) there can be inks used for printing images and other features deemed necessary by a respective banking authority. It is known that some inks used for printing can exhibit electromagnetic properties such that a sensing system can be used to verify its presence or characteristics. Banknotes are sometimes constructed using multiple layers of different materials to form a substrate. In some cases one or more of these layers exhibit electromagnetic properties such that a sensing system can be used to verify its presence or characteristics.
Other items of currency (e.g. coins or tokens) can be constructed using at least one component or material that exhibits electromagnetic properties. Some currently circulating coins are constructed using more that one material (e.g. cladded coins, platted coins, or bi-color coins), and in some cases at least one of the materials used exhibit electromagnetic properties. In automated transaction machines, there can be provided a sensing unit that is capable of verifying the presence or characteristics of a given material in an item of currency. For the purposes of the disclosure the term “item of currency” includes, but is not limited to, banknotes, bills, coupons, security papers, checks, valuable documents, coins, tokens, and gaming chips.
The authentication of items of currency can also occur in processing equipment used by central banking institutions for sorting and evaluation. This equipment can include an authentication unit configured to sense at least one electromagnetic property of an item of currency for the purpose of recognition and/or authentication.